1. Field of the Invention
The present invention relates to an arrangement for engaging and retaining a web-like material, in particular a plurality of superposed webs of cloth, the uppermost cloth web of which is covered by a foil of at least substantial air-impermeability for a cutting out machine or cloth cutter which may be positioned intermediate a material infeed table and a material take-off device, including an endless bristle belt which is movable in the material-conveying direction of the cloth cutter, and between the bristles of which there may be exerted a suction pressure on the web material.
2. Discussion of the Prior Art
It is already known in connection with an arrangement for the automatic cutting of flat material webs to provide bristle mats which are positioned behind each other in the material-conveying direction, in the region of their longitudinal edges extending in the material-conveying direction these mats being subjected to a suction pressure or vacuum which thereby acts intermediate the bristles of the bristle mats against the superposed material. In essence, this signifies that the material lying on the respective bristle mat is clamped at its end regions extending parallel to the aforementioned material-conveying direction through the therein presently effective suction pressure. However, it is disadvantageous in that there must be exerted relatively high tensile forces on the material in order to be able to at all pull this material over the bristle mats in the aforementioned conveying direction. It is also disadvantageous that the generation of the vacuum or suction pressure along the longitudinal edges of the bristle mats extending in the material-conveying direction does not ensure that the material to be cut will remain flat on the bristle mats when the cutting device provided performs the cutting actions in the mentioned conveying direction. In this instance, this may lead to a bunching up of the material in the pertinent direction of movement.
Furthermore, it is also known to provide an endless bristle belt on which the material which is presently to be cut be employed in connection with a device for cutting a web-like material. However, this bristle belt has an air-permeable bristle support which, within the zone of material conveyance, is guided over a porous support plate, and which is so connected with a vacuum generator as to generate a suction effect through the air-permeable bristle support against the web-like material supported on the bristles thereof. Although in most instances web-like materials can be satisfactorily engaged and retained with the assistance of this type of bristle belt and, moreover, there are overcome the difficulties which are expected in connection with the heretofore considered known arrangement; however, in a few instances it may prove to be disruptive that the applicable bristle band has a relatively low number of bristles. With regard to bristle mats of the type employed as in the case of the previously considered arrangement, an air-permeable bristle belt has already less bristles based on the fact of its air permeability alone. The air permeability of the bristle support of the bristle belt is usually achieved in that the bristle support is perforated. However, no bristles can be present at the locations provided for the perforations. This may exert a disadvantageous effect during the engagement and retention of extremely thin webs of cloth.